Production of commercial borax from na2o.2b2o3.4h2o



Patented July 24, 1928. I g

UNITED STAT rrnomes I 1,678,381 PATENT" OFFICE.

PRODUCTION OF COMMERCIAL BORAX FROM NfizO-ZBzOsAHaO.

No Drawing.

Although my present inventionis entitled as referring to the production of borax, it should be understood not only that the product aimed at may be the ordinary .prismatic borax of commerce, N a O.2B O .10H O, but that my present invention relates more particularly, so far as its essential novelty is concerned, to amethod of producing, from a newly discovered and slowly dissolving borate which I have called Rasorite (containing four molecularproportions of water to one molecularproportion of Na 0 two moleculanproportions of B 0 a borax solution,-from which the ordinary prismatic borax orother borates may be obtained in a known manner. Y

My present invention relates, in particular, to a recently discoverednaturally-occurring sodium borate whose utilization has appeared unpromisin ',-by reason of the fact that, although capable of ultimately dissolving in water, up to the known point of saturationof sodium borates, this new borate enters into solution, even in boiling water, at an exceedingly slow rate.

An analysis of selected specimens of the newly discovered borate has shown its composition to be Na O2B O AI-I O; so that this substance is seen to be one of that known 7 series of alkali-metal borates which includes the prismatic borax of commerce (containing ten molecular proportions of water to two molecular proportions of B O ),another known member of this series being the socalled octohedral borax, Na O.2B O .5H O.' Particles which result from crushin Rasorite are often splinter-like inform; an even when finely ground, they are so resist'ant to the "solvent action of hot water as to render reliance upon usual methods of subdivision and solution unsatisfactory.

As affording a rough comparison of solu- ,tion rates (all of "the heretofore known sodium borates containing water of crystallization or water of combination being quickly soluble in water at 100 (3., even when the introduced crystals are of a size such as A in diameter,-or larger) I may mention that a crystal weighing 1.0 gram remained in water at 100 (3., for 55 minutes before complete solution was effected; whereas a crystal of prismatic borax weighing 1.0 gram required but 30 seconds to effect its complete solution under like conditions; and it is accordingly an object of my invention to pr( and Application filed January 12, 1927. Serial No. 160,778.

merely to a temperature slightly above 212 R, I find that a less expenditure of fuel is required during actual solution, and that fine grinding of the Rasorite is rendered unnecemary, i I' sub'ect the same even to a comparatively mo crate preliminary heat treatment,as by exposing the same in ovens, or merely on shelves or on a conveyor,

to escaping flue gases, or the like, such as may be produced incidentally to the operation of a steam boiler or an equivalent apparatus utilizing fuel for any purpose whatever. a

In the practice of my presentinvention, in preference to disposing the Rasorite upon shelves in flues or 1n ovens, I take Rasorite as it comes from the mines or preferably of a size to permit the same to pass a 2" mesh-and interm1ttently or continuously pass the same through any heated zone,-not necessarily leaving the same therein beyond a period sufiicient to permit the heat to penetrate the crystals and todrive therefrom an appreciable proportion of the water of combination,-thi's being found to have adisruptive effect upon the crystal structure. Subsein; cinemas, or LONG men, CALIFORNIA, assrenon T0 racmrc coAs'r sonax comrAnY,.A conrosa'rron or NEVADA.

the mentioned heat treatment, may be quick- 7 1y dissolved in hot water, or in any suitable mother liquod heated approximately to the boiling point of water; and any desired steps (as, mere filtration) may be employed for the separation of gangue or impurities from the resultant vsolution.

Crystallization ofthe desired prismatic borax may be efi'ected by cooling in a known manner,-the strength of the solution being preferably such that no crystals appear above about 140? F. .Any suitable watery medium may be used for' the mentioned solvent action,'as, a hotmother liquor-ob tained by treating a previous batch of ore in the described manner; and the preheated ore may be introduced thereto while still hot.

It will be recognized that the described preliminary treatment aims not only at an opening up physical change rendering the same more readily soluble, but at an avoidance of fine grinding, at a minimization of expenditures for fuel, and at an economy in time, that, as a result of the described preliminary heating (in which I may employ, for example, temperatures above 240 F.) solution may be quickly effooted, in the indicated manner;. and that the maintenance of the mentioned concentration, during the ,final cooling, aims primarily to avoid the production of undesired forms of borax,such as that which includes five molecular proportions, rather than ten' molecular proportions of water to twomolecular' proportions of B 0 butit should nevertheless be understood that various tea- 7 tures-of my invention might be independent- 1y. employed, and also minor modifications thereof might easily be devised, by those skilled in the'arts to which this case relates, without involving the slightest departure from the spirit and scope of my invention ,as the same is indicated above and in the i01- lowing claims. I

I claim as my invention:

1. In the production of commercial borax from a naturally-occurring sodium borate in the Rasorite,.

which resists solution, a method which includesr subjecting said mineral to a temperature. suflicient to render the mineral less resistant to solution in water, dissolving the same in a watery medium; and c sta'llizmg a commercial borax from the resu tant solution.

from a naturally-occurring sodium borate which resists solution, a method which in- 2. In the production of prismatic borax fined in claim 1 in which the mentioned heating is affected by means of flue gases.

5. In the production of a borax solution from an alkali-metal borate which resists solution, the step which consists in heating said alkali borate to a temperature above the boiling point of water.

In testimon whereof, I have hereunto set my hand at os Angeles, California, this 6t day ofJanuary, 1927.

THOMAS M. CRAMER. 

